Revenue (Revenue by Geographic Location) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 28,546	$ 23,715	$ 55,751	$ 50,324
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue	22,182	18,656	43,338	39,346
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue	5,683	4,621	11,035	9,654
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 681	$ 438	$ 1,378	$ 1,324